Circuitous passageway for drying copy sheets

ABSTRACT

Apparatus forming a circuitous passageway in a copying device comprising a large diameter squeeze roller and a plurality of smaller diameter squeeze rollers of a smaller width pressing against the large diameter squeeze roller. Copy sheets released from the developing liquid tank are introduced one after another into this circuitous passageway to squeeze out the developing liquid from the copy sheets for drying the same and to change the direction of movement of the sheets. The small diameter squeeze rollers are arranged such that one of them or a center squeeze roller is disposed on the center peripheral line of the large diameter squeeze roller near the inlet of the circuitous passageway and the remainder are disposed in two rows symmetrical with respect to the center peripheral line of the large diameter squeeze roller, the two rows of rollers being spaced apart a greater distance toward the opposite edges of the periphery of the large diameter squeeze roller in going from the center squeeze roller in the direction of movement of the copy sheets along the circuitous passageway.

United States Patent, [191 Yamada et a1.

[111 3,797,127 51 Mar. 19, 1974 CIRCUITOUS PASSAGEWAY FOR DRYING COPY SHEETS [75] Inventors: Hiroshi Yamada, Ichikawa; Hiroshi Hirose, Tokyo, both of Japan [56] References Cited UNITED STATES PATENTS 3,740,867 6/1973 Hamaguchi 34/95 3.492.458 l/1970 White et a1. 219/216 Shaler et al.. Lovett .1 34/162 Primary Examiner.lohn .l. Camby Assistant Examiner-Henry C. Yuen Attorney, Agent, or FirmCooper, Dunham, Clark, Griffin & Moran [5 7] ABSTRACT Apparatus forming a circuitous passageway in a copying device comprising a large diameter squeeze roller and a plurality of smaller diameter squeeze rollers of a smaller width pressing against the large diameter squeeze roller. Copy sheets released from the developing liquid tank are introduced one after another into this circuitous passageway to squeeze out the developing liquid from the copy sheets for drying the same and to change the direction of movement of the sheets. The small diameter squeeze rollers are arranged such that one of them or a center squeeze roller is disposed on the center peripheral line of the large diameter squeeze roller near the inlet of the circuitous passageway and the remainder are disposed in two rows symmetrical with respect to the center peripheral line of the large diameter squeeze roller, the two rows of rollers being spaced apart a greater distance toward the opposite edges of the periphery of the large diameter squeeze roller in going from the center squeeze roller in the direction of movement of the copy sheets along the circuitous passageway.

9 Claims, 7 Drawing Figures PATENTEUHAR 19 I974 SHEET 1 [IF 2 FIG. |(PRIOR ART) PATENTED MR 1 9 I974 SHEEI 2 0F 2 FIG.7

CIRCUITOUS PASSAGEWAY FOR DRYING COPY SHEETS BACKGROUND OF THE INVENTION This invention relates to a circuitous passageway for drying copy sheets released from the developing liquid tank of an electrophotographic copying apparatus of the wet developing type.

In an electrophotographic copying apparatus of the wet developing type, copy sheets released from its developing liquid tank have hitherto been dried as by blowing a dry hot air stream against them so as to fix the image formed thereon.

It goes without saying that each copy sheet is preferably in a thoroughly dry condition when ejected from the copying apparatus. However, the provision of a drying device of a sufficiently large capacity between the developing liquid tank and the copy sheet outlet port entails an increase in the demand for space in the machine and a resultant increase in the overall size of the machine. Therefore, it is customary to provide a copy sheet receiving tray outside the copy sheet outlet port and to subject the copy sheets ejected from the outlet port on to the copy sheet receiving tray to a stream of dry air so as to dry the copy sheets outside the apparatus.

Some disadvantages are associated with this method of drying the copy sheets outside the apparatus. For one thing, the operation is time consuming, and it becomes necessary to operate the apparatus merely to dry the copy sheets after all other operations have been finished. For another, it is impossible to achieve satisfactory results by this method when a number of copy sheets are ejected from the machine consecutively because the next following sheet is ejected from the machine before the preceding sheet is not dried yet and overlies the partly dried sheets, so that all the sheet remain wet in spite of the effort to dry them.

The best way to obviate this problem is to carry out drying of copy sheets inside the apparatus. Any attempt to dry copy sheets inside the apparatus will surely fail unless the problem of how to prevent an increase in the overall size of the apparatus is solved.

Proposals have been made to provide a circuitous passageway in a copying apparatus for causing copy sheets released from the developing device to move through it so that the copy sheets can be thoroughly dried before being ejected from the apparatus without increasing the overall size of the machine. One example of these proposals is. shown in FIG. 1.

In FIG. 1, there is shown-a developing liquid tank 1 containing therein a developing liquid 2. A copy sheet passageway of a curvature substantially similar to the arc of a circle is formed in the developing liquid tank 1 by a plurality of guide fins 3 disposed normal to the plane of a copy sheet and in side-by-side relation with one another and a curved guide plate 4 disposed above the fins 3. The radius of curvature of he passageway 5 may vary depending on the conditions under which developing is carried out.

A pair of delivery rollers 6 and 7 pressing against each other and rotating in the directions of arrows are disposed near the entrance to the passageway 5 rightwardly upwardly of the developing liquid tank 1. A copy sheet 8 shown about to be nipped by the rollers 6 and 7 may be an electrophotographic photosensitive sheet on which an electrostatic latent image is formed by electric charging and exposing to an optical image of an original or an electrostatic recording sheet on which an electrostatic latent image is formed by means of contact electrodes. The copy sheet 8 is nipped by the rollers 6 and 7 and introduced into the passageway 5 through which it moves while being immersed in the developing liquid 2 to develop and convert the electrostatic latent image into a visible image.

Squeeze means 11 disposed near the exit of the passageway 5 leftwardly upwardly of the developing liquid tank comprises a pair of squeeze rollers pressing against each other, one being a metallic roller 9 and the other being a sponge roller 10. A pair of blotter rollers 12 and 13 pressing against each other are disposed downstream of the squeeze means 11. The rollers 9, 10, 12, and 13 rotate in the directions of arrows to move the copy sheet 8 after being developed while squeezing water out of the copy sheet and absorbing moisture therefrom.

The guide plate 4 and the metallic roller 9 of the squeeze means 11 may be used concurrently as opposite electrode plates by impressing a suitable bias voltage thereon or by grounding them. The squeeze means 11 is not limited to the specific form shown and illustrated but it may comprise any other combination of rollers as desired.

The copy sheet 8 moved leftwardly upwardly away from the passageway 5 by the squeeze means 11 and the blotter rollers 12 and 13 is subjected to an air stream ejected from a blower 14 disposed leftwardly upwardly of the rollers 12 and 13 to dry the copy sheet. While being dried in this way, the copy sheet 8 is caused to change its direction of movement downwardly and moves downwardly along an endless belt 16 of belt conveyor means 15 which is disposed in a slightly inclined position.

The belt conveyor means 15 further comprises a pair of belt rollers 17 and 18 about which the endless belt 16 is trained and moves in the direction of an arrow a. Another belt conveyor means 22 comprising belt rollers 19 and 20 and an endless belt 21 trained about them is disposed such that it is juxtaposed to a substantially lower half of the belt conveyor means 15 to help the copy sheet 8 in its movement along the endless belt 16. In cooperation with the blower 14, the conveyor belt 15 causes the copy sheet 8 to change its direction of movement and move downwardly along a circuitous passageway 5a between the two conveyor'means l5 and 22 while being dried by the air stream till finally the copy sheet 8 is ejected on to a copy sheet tray 23.

In the illustrated example, the circuitous passageway 5a is formed by the blower 14 and the belt conveyor means 15. The circuitous passageway of this type has a disadvantage in that the copy sheet moving therethrough may deviate from the passageway or catch against the belt when there is a variation in the quality of copy sheets or there are changes in the conditions under which the copy sheets move along the circuitous passageway, such for example as the rate of movement of the air stream.

SUMMARY OF THE INVENTION This invention has as one of its objects the provision of a circuitous passageway for drying copy sheets for an electrophotographic copying apparatus of the wet developing type which is formed by a large diameter squeeze roller and a plurality of small diameter rollers of a small width pressing against the large diameter squeeze roller for drying the copy sheets and changing the direction of their movement.

Another object of the invention is to provide a circuitous passageway of the character described in which the small diameter squeeze rollers are arranged such that one of them or a center squeeze roller is disposed on the center peripheral line of the large diameter squeeze roller near the inlet of the circuitous passageway and the remainder are disposed in two rows symmetrical with respect to the center peripheral line of the large diameter squeeze roller, two rows of rollers being spaced apart a greater distance toward the oppo- 'site edges of the periphery of the large diameter square roller in going from the center squeeze roller in the direction of movement of the copy sheets along the circuitous passageway.

Still another object of the invention is to provide a circuitous passageway of the character described in which the small diameter squeeze rollers of a small width arranged in two rows are inclined with respect to the axis of the large diameter squeeze roller toward the opposite edges of the periphery of the large diameter squeeze roller, thereby permitting folding of marginal portions of the copy sheets or formation of wrinkles in the copy sheets to be precluded.

According to this invention, there is provided a circuitous passageway for drying copy sheets for a copying apparatus of the wet developing type which permits copy sheets positively and smoothly to take a roundabout way afterbeing developed and which permits the copy sheet to be dried in good condition without the copy sheets being wrinkled or having their marginal portions folded as often happens when the circuitous passageway is formed by a large diameter squeeze roller and a squeeze roller of a large width pressing against the large diameter squeeze roller.

Other and additional objects as well as features and advantages of the invention will becomeevident from the description set forth hereinafter when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a conventional circuitous passagewayfor drying copy sheets for an electrophotographic copying apparatus of the wet developing type;

FIG. 2 is a sectional view of the circuitous passageway for drying copy sheets for an electrophotographic copying apparatus of the wet developing type comprising one embodiment of this invention;

FIG. 3 is a developmental view showing the arrangement of the small diameter squeeze rollers of a small width for forming the circuitous passageway shown in FIG. 2;

FIG. 4 is a sectional view of the circuitous passageway for drying copy sheets for an electrophotographic copying apparatus of the wet developing type comprising another embodiment of the invention;

FIG. 5 is a developmental view showing the arrangement of the small diameter squeeze rollers of a small width for forming the circuitous passageway shown in FIG. 4; v

FIG. 6 is a sectional view of one form of support means for each of the small diameter squeeze rollers of a small width shown in FIG. 4; and

FIG; 7 is a perspective view of another form of support means for the small diameter squeeze rollers of a small width.

DESCRIPTION OF PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIG. 2 and FIG. 3, and

another embodiment with reference to FIG. 4 and FIG.

5. Parts designatedby like reference characters in FIG. I and FIG. 2 to FIG. 5 have the same construction and perform the same function, so that detailed description of the parts which have already been described with reference to FIG. 1 will be omitted in the interest of brevity. 1 V

In FIG. 2, the copy sheet 8 developed by the developing liquid-as it'passes through the developing'liquid tank 1 is moved leftwardly upwardly of the squeeze means 11 as the developing liquid is squeezed out of the copy sheet 8 by the squeeze means 11.

A large diameter squeeze roller 24 made of metal, plastic, hard rubber or like material is disposed left wardly of the squeeze means 11 in FIG. 2 and adapted to be driven to rotate in the direction of an arrow b at a peripheral velocity which is equal to the rate of movement of the copy sheet 8.

As shown in FIG. 2 and FIG. 3, a blotter roller 25 of a width corresponding to the width of the copy sheet 8 is disposed above the large diameter squeeze roller 24 to press against the peripheral surface thereof. Disposed downstream of the blotter roller 24 are a plurality of smaller diameter squeeze rollers of a smaller width 26, 27a, 27b, 28a, 28b, 29a, 29b, 30a and 30b which also press against the peripheral surface of the large diameter squeeze roller 24 to form the circuitous passageway 5a therebetween.

FIG. 3 shows the arrangement of the small diameter squeeze rollers of a small width in a developmental plan view. It will be seen that the small diameter squeeze rollers are disposed such that one of them or a center squeeze roller 26 is disposed on the center peripheral line of the large diameter squeeze roller 24 near the inlet of the circuitous passageway 5a and the remainder are disposed in two rows, one comprising the rollers 27a, 28a, 29a and 30a and the other comprising the rollers 27b, 28b, 29b and 30b, arranged symmetrically with respect to the center peripheral line of the large diameter squeeze roller, and the adjacent rollers in the two rows of rollers being spaced apart a greater distance toward the opposite edges of the periphery of the large diameter squeeze roller in the direction of movement of the copy sheet 8 along the circuitous passageway Sa.

The roller 24 is supported by a shaft.24a (FIG. 2) while the rollers 25. and 26 are supported by shafts 31 and 32 respectively. The rollers 27a and 27b are supported by a common shaft 33, the rollers 28a and 28b by a common shaft 34, the rollers 29a and 29b by a common shaft 35, and the rollers 30a and 30b by a common shaft 36. All the shafts 24a, 31, 32, 33, 34, 35 and 36 are rotatably supported by support plates 37 and 38 at opposite ends. The shafts supporting the small diameter squeeze rollers may be spaced apart an equal distance from one another or the spacing between the adjacent shafts may be gradually reduced in going from the entrance to the exit of the circuitous passageway 5a. By gradually reducing the spacing between the adjacent rollers, it is possible to more effectively prevent folding of marginal portions of the copy sheets.

As aforementioned, the circuitous passageway 50 according to this invention is formed by the large diameter squeeze roller 24 and the smaller diameter squeeze rollers of a smaller width pressing against the roller 24. The copy sheet 8 introduced into the circuitous passageway 5a can smoothly move along the peripheral surface of the roller 24 while being extended to right and left without developing folding of marginal portions of the copy sheet 8 or without the copy sheet 8 catching against the components of the passageway 5a.

The blotter roller 25 and small diameter squeeze rollers 26, 27a, 27b, 28a, 28b, 29a, 29b, 30a and 30b are made of sponge, blotting paper or other hygroscopic material, so that the developing liquid can be removed positively from the copy sheet 8 while the latter moves through the circuitous passageway 5a. The provision of the blower 14 above the large diameter roller 24 is effective to dry the copy sheet 8 completely by subjecting the same to a stream of dry air ejected therefrom against the copy sheet 8 while the latter moves through the passageway 50 and has its moisture content removed by the blotter roller and small diameter squeeze rollers, before the copy sheet 8 is ejected on to the copy sheet receiving tray 23.

The large diameter squeeze roller 24 may be made of a hygroscopic material, or made in the form of'a cylinder having a built-in heater 24b such as shown in FIG. 2.

FIG. 4 and FIG. 5 show another embodiment of the invention. As shown in FIG. 4, a large diameter squeeze roller 40 and a blotter roller 41 and small diameter squeeze rollers of a small width 42, 43a, 43b, 44a, 44b, 45a, 45b, 46a and 46b pressing against the peripheral surface of the squeeze roller 40 form therebetween the circuitous passageway 5a into which the copy sheet 8 is introduced and from which it is ejected leftwardly downwardly of the passageway in FIG. 4. While moving through the passageway, the copy sheet 8 is subjected to a stream of dry air (or a hot blast) ejected from the blower 14 so that it is thoroughly dried.

FIG. 5 shows the manner in which the smaller diameter squeeze rollers of a small width shown in FIG. 4 are arranged on the peripheral surface of the large diameter squeeze roller. Itwill be seen that, although the rollers 42, 43a, 43b, 44a, 44b, 45a, 45b, 46a and 46b are disposed substantially in the same manner as the small diameter rollers ofa small width 26, 27a, 27b, 28a, 28b, 29a, 29b, 30a and 30b of the first embodiment, the rollers arranged in two rows differ from the rollers arranged in two rows of the first embodiment in that the former are inclined with respect to the axis of the large diameter squeeze roller 40 toward the opposite edges of the periphery of the roller 40.

The roller 40 is supported by a shaft 40a (FIG. 4) while the rollers 41 and 42 are supported by shafts 47 and 48 respectively. The rollers 43a and 431: are supported by a common shaft 49, the rollers 44a and 44b by a common shaft 50, the rollers 45a and 45b by a common shaft 51 and the rollers 46a and 46b by a common shaft 52. All the shafts 40a, 47, 48, 49, 50, 51 and 52 are rotatably supported by support plates 53 and 54 at opposite ends.

The shafts 49, 50, 51 and 52 support the rollers 43a, 43b, 44a, 44b, 45a, 45b, 46a and 46b at support portions 49a, 49b, a, 50b, 51a, 51b 52a and 52b respectively which are inclined with respect to the axis of each shaft such that the rollers are inclined outwardly with respect to the axis of the large diameter squeeze roller 40. By this arrangement, the rotational force of the rollers-43a, 43b, 44a, 44b, 45a, 45b, 46a andv46b act on the copy sheet 8 such that the latter is stretched transversely toward opposite sides thereof when moving through the circuitous passageway 5a.

FIG. 6 shows an example of the manner in which each small diameter roller is supported by the support portion of the respective shaft. A shaft B supporting a roller A is formed with stepped portions B1 and B2, and an E ring C is fitted over each stepped portion. Then, the shaft B is bent as shown to bring the roller A to an inclined position.

The arrangement in which each of the small diameter squeeze rollers arranged in two rows on the peripheral surface of the large diameter squeeze roller is inclined as aforementioned is more advantageous in enabling the copy sheet 8 to move smoothly through the circuitous passageway without having its marginal portions folded or without the copy sheet catching against the components of the passageway than the arrangement in which the small diameter squeeze rollers are not inclined. This is because the arrangement is effective to stretch the copy sheet transversely toward opposite sides thereof.

FIG. 7 shows another form of support means for the small diameter squeeze rollers of a small width. The support means comprises a curved support plate 61 disposed along the peripheral surface of the large diameter squeeze roller 40 in covering relationship, and a plurality of arms 62 of the inverted U-shape. The arms 62 may be arranged such that each of them supports one of the small diameter squeeze rollers of a small width in an inclined position or non-inclined position. The small diameter squeeze rollers of a small width supported by the arms 62 perform the same function as the small diameter squeeze rollers of a small width shown in FIG. 3 and FIG. 5.

What is claimed is:

1. Apparatus forming a circuitous passageway for drying copy sheets for an electrophotographic copying apparatus of the wet developing type comprising a large diameter squeeze roller disposed on one side of a path of copy sheets released from a developing liquid tank; and a plurality of smaller diameter squeeze rollers being arranged such that one of them is disposed on the center peripheral line of the large diameter squeeze roller near the inlet of the circuitous passageway and the remainder are disposed in two rows symmetrical with respect to the center peripheral line of the large diameter squeeze roller, the two rows of rollers being spaced apart a greater distance toward the opposite edges of the periphery of the large diameter squeeze roller in going from the center line squeeze roller in the direction of movement of the copy sheets along the circuitous passageway, whereby the copy sheets can be dried and the direction of their movement can be changed while passing through the passageway.

2. Apparatus as in claim 1 wherein said plurality of smaller diameter squeeze rollers arranged in two rows are inclined with respect to the axis of the large diameter squeeze roller toward the opposite edges of the periphery thereof whereby the copy sheet moving through the circuitous passageway can be stretched transversely.

3. Appparatus as in claim 1 wherein adjacent ones of said plurality of smaller diameter squeeze rollers are disposed on common shafts on the peripheral surface of the large diameter squeeze roller and the spacing between shafts supporting the small diameter squeeze rollers is gradually reduced in going from the inlet of the circuitous passageway toward the outlet thereof.

4. Apparatus as in claim 1 wherein said large diameter squeeze roller is made of a hard material and said plurality ofv smaller diameter squeeze rollers are made of a hygroscopic material. A

5. Apparatus as in claim 1 wherein said large diameter squeeze roller is made of a hygroscopic material.

6. Apparatus as in claim 1 wherein said large diameter squeeze roller is in the form of a cylinder having a built-in heater.

7'. Apparatus as in claim 3 wherein said plurality of smaller diameter squeeze rollersare inclined with respect to the axis of the large diameter squeeze roller by bending the shafts supporting said rollers.

8. Apparatus as in claim 1 wherein said plurality of smaller diameter squeeze rollers are supported by support arms of the U-shape attached to the underside of a curved support plate mounted along the peripheral surface of the large diameter squeeze roller in covering relationship 9. Apparatus as in claim 1 wherein a blower for supplying a stream of air for drying copy sheets moving the circuitous passageway is mounted near the circuitous passageway. 

1. Apparatus forming a circuitous passageway for drying copy sheets for an electrophotographic copying apparatus of the wet developing type comprising a large diameter squeeze roller disposed on one side of a path of copy sheets released from a developing liquid tank; and a plurality of smaller diameter squeeze rollers being arranged such that one of them is disposed on the center peripheral line of the large diameter squeeze roller near the inlet of the circuitous passageway and the remainder are disposed in two rows symmetrical with respect to the center peripheral line of the large diameter squeeze roller, the two rows of rollers being spaced apart a greater distance toward the opposite edges of the periphery of the large diameter squeeze roller in going from the center line squeeze roller in the direction of movement of the copy sheets along the circuitous passageway, whereby the copy sheets can be dried and the direction of their movement can be changed while passing through the passageway.
 2. Apparatus as in claim 1 wherein said plurality of smaller diameter squeeze rollers arranged in two rows are inclined with respect to the axis of the large diameter squeeze roller toward the opposite edges of the periphery thereof whereby the copy sheet moving through the circuitous passageway can be stretched transversely.
 3. Appparatus as in claim 1 wherein adjacent ones of said plurality of smaller diameter squeeze rollers are disposed on common shafts on the peripheral surface of the large diameter squeeze roller and the spacing between shafts supporting the small diameter squeeze rollers is gradually reduced in going from the inlet of the circuitous passageway toward the outlet thereof.
 4. Apparatus as in claim 1 wherein said large diameter squeeze roller is made of a hard material and said plurality of smaller diameter squeeze rollers are made of a hygroscopic material.
 5. Apparatus as in claim 1 wherein said large diameter squeeze roller is made of a hygroscopic material.
 6. Apparatus as in claim 1 wherein said large diameter squeeze roller is in the form of a cylinder having a built-in heater.
 7. Apparatus as in claim 3 wherein said plurality of smaller diameter squeeze rollers are inclined with respect to the axis of the large diameter squeeze roller by bending the shafts supporting said rollers.
 8. Apparatus as in claim 1 wherein said plurality of smaller diameter squeeze rollers are supported by support arms of the U-shape attached to the underside of a curved support plate mounted along the peripheral surface of the large diameter squeeze roller in covering relationship.
 9. Apparatus as in claim 1 wherein a blower for supplying a stream of air for drying copy sheets moving the circuitous passageway is mounted near the circuitous passageway. 